FROM.you

IBAN Format Checker

The checker confirms that the entered value has a plausible IBAN structure and that its ISO 13616 check digits satisfy the mod-97 calculation. Processing stays in the browser.

Use this as a typo and checksum screen before authorization, never as evidence that the recipient owns the account.

Format check only

No bank or account-owner lookup takes place. A passing checksum is not permission to pay.

Inspect the characters and checksum

Spaces are fine. The value stays in this browser tab.

CountryGBUnited Kingdom
Check digits82Mathematical error check
National account sectionWEST 1234 5698 7654 32Structure varies by country
Characters22 / 22Expected national length
Ready for a local check

The inspector will test general structure, a known national length where available, and the ISO mod-97 checksum.

Normalize

Remove display spaces and capitalize letters.

Rearrange

Move the first four characters to the end.

Translate

Convert letters to values from 10 to 35.

Test

A valid checksum leaves a remainder of 1.

The exact boundary of this check

The checker removes spaces, moves the first four characters to the end, translates letters to numbers and evaluates the result modulo 97. A remainder of 1 indicates a valid checksum; it does not prove the account exists or belongs to the intended recipient.

See the validation method →

What an IBAN format and checksum check can confirm

A valid checksum detects many typing errors, but it does not prove that the account exists, is open, can receive the intended currency or belongs to the person you mean to pay.

Read an IBAN as three different signals

Country code
Two letters identify the national IBAN system whose length and internal structure should apply.
Check digits
Two digits support an error-detection calculation across the complete IBAN.
BBAN
The remaining national section can contain bank, branch and account elements in a country-specific arrangement.

Example: a checksum can pass while the payment is still unsafe

An invoice can contain a structurally valid IBAN belonging to a fraudster. The checksum only evaluates the characters; it does not query a bank or compare the account holder with the intended recipient.

After a valid result, confirm the recipient and any new or changed instructions through a separate trusted channel. Use payee-name confirmation where the relevant payment system provides it.

Use the result as one verification layer

Structure

The value begins with a country code and check digits and uses the permitted alphanumeric form.

Checksum

The rearranged and translated value produces the required mod-97 remainder.

Account verification

Not performed. FROM.you sends no request to a bank, registry or account holder.

What the inspector deliberately does not claim

This lightweight checker validates general structure and checksum only. National IBAN lengths and bank-code positions vary by country; confirm the official country format and recipient details before payment.

Confirm the recipient through a trusted channel and use any payee-name check offered by the sending bank. Recheck changed payment instructions even when the replacement IBAN passes.

Questions a checksum result cannot answer

Does a valid IBAN mean the account exists?

No. A valid checksum is a mathematical consistency check, not a live account lookup.

Does FROM.you transmit the IBAN?

No. The checker runs locally in the browser and the form does not submit the value to FROM.you.

Can an IBAN identify the account owner?

No. Use the recipient-verification process offered by your bank or payment system and independently confirm changed instructions.

Standards behind the format inspection

ISO defines the IBAN framework, while SWIFT publishes the national registry used by financial institutions. This browser check applies the general character and mod-97 rules and a maintained set of national lengths.

Continue from format accuracy to recipient safety

Read the IBAN structure and safe-use guide →

After the checksum, review international banking account and routing requirements before relying on the details.